1. Field
The disclosed concept relates generally to electrical switching apparatus and, more particularly, to electrical switching apparatus, such as remote control subminiature circuit breakers with embedded arc fault protection. The disclosed concept also relates to systems employing remote control subminiature circuit breakers with embedded arc fault protection.
2. Background Information
Electrical switching apparatus include, for example, circuit switching devices; circuit interrupters, such as circuit breakers; network protectors; contactors; motor starters; motor controllers; and other load controllers.
One use of miniature or subminiature circuit breakers, for example, is in devices or environments with limited space and/or weight limitations, such as, for example and without limitation, aircraft electrical systems, where they not only provide overcurrent protection, but also serve as switches for turning equipment on and off. As such, they are subjected to heavy use and, therefore, must be capable of performing reliably over many operating cycles.
Subminiature circuit breakers have the typical circuit breaker components, such as a non-conductive housing, an external actuator, at least two external terminals structured to be coupled to a line and a load, a pair of separable contacts including a first, stationary contact electrically coupled to one external terminal and a second, movable contact couple to the other external terminal, an operating mechanism structured to move the separable contacts between a first, closed position wherein the contacts engage and electrically connect each other, and a second position wherein the contacts are separated, and a trip device structured to latch the operating mechanism in the first position until an over-current condition occurs. The operating mechanism includes a bias element (e.g., without limitation, spring) biasing the separable contacts toward the second position. Thus, when the trip device is actuated, the latch releases the operating mechanism and the separable contacts move to the second position. The operating mechanism is also coupled to the external actuator. The external actuator is structured to move the separable contacts to the first position after a trip event, or may be used to manually separate the contacts.
Known circuit breakers having arc fault protection include a trip device with at least two tripping mechanisms; one mechanism for an over-current situation and one mechanism for an arc fault on the load side of the circuit breaker. The over-current mechanism typically includes an elongated bimetal element that bends in response to temperature changes. The act of bending actuates the latch, thereby allowing the operating mechanism to separate the separable contacts. Heat is created in response to current passing through the bimetal element. Thus, the greater the amount of current, the greater the degree of bending. The electronic arc fault mechanism of such breakers includes an electronic arc fault detector and a solenoid assembly. When the electronic arc fault detector sensed an arc, a the solenoid sends a pulse and actuates the trip device. Among other disadvantages, such designs were relatively large occupying a significant amount of space.
Additionally, under certain circumstances, it would be may be desirable to provide remote control operation of subminiature circuit breakers.
There is, therefore, room for improvement in electrical switching apparatus, such as subminiature circuit breakers, and in systems employing the same.